A few questions from a newbie

[trimmy]

I am getting a 1986 chevy c20 with a 454 in it on saturday. The truck is in great shape for an 86 that has lived it life in Ohio. The truck when cold idles really high how do I adjust the carb(stock quadrajet) Can I and should I swap in a new carb without changing anything else such as the intake? My only plans for the truck is delete the emissions, put a set of header/mufflers and maybe an intake/carb then drive it. Its just a truck to run to lowes in and pick up firewood and and little projects. I am a total NEWBIE when it comes to gassers/carbs I am a diesel guy. Also the owner stated the truck does not switch from the drivers tank to the passenger tank what is usually the culprit?

Thanks for your help

[bk2life]

Originally Posted by trimmy

I am getting a 1986 chevy c20 with a 454 in it on saturday. The truck is in great shape for an 86 that has lived it life in Ohio. The truck when cold idles really high how do I adjust the carb(stock quadrajet) Can I and should I swap in a new carb without changing anything else such as the intake? My only plans for the truck is delete the emissions, put a set of header/mufflers and maybe an intake/carb then drive it. Its just a truck to run to lowes in and pick up firewood and and little projects. I am a total NEWBIE when it comes to gassers/carbs I am a diesel guy. Also the owner stated the truck does not switch from the drivers tank to the passenger tank what is usually the culprit?

1.high idle, tap gas pedal to get off the hihg idle cam.
2.why delete anything/change anytying if you are just going to drive it?
3.gas motor is same in theory as deisel, more in more out (power)
4.tank switch on dash, or tank selector valve on frame, or bad wiring, bad fuse.

[trimmy]

Originally Posted by bk2life

1.high idle, tap gas pedal to get off the hihg idle cam.
2.why delete anything/change anytying if you are just going to drive it?
3.gas motor is same in theory as deisel, more in more out (power)
4.tank switch on dash, or tank selector valve on frame, or bad wiring, bad fuse.

1. I want it lower, its to high why not adjust it to where it needs to be?
2. I will eventually end up doing something, I always say I wont but I always do. it also deletes a lot of stuff under the hood freeing up a lot of space.
3. Yea I understand that
4. Ok i'll check those

[geezer#99]

There's a high idle adjustment screw right under the vacuum pot on the front passenger side of the carb. A phillips screwdriver will work.

[f18delta]

When my 350's cold in the morning here in OK, it idles high as well for awhile. Like bk said, tap the gas pedal after a little while to see if it idles down.

I'll be adjusting the carb and timing on it (hopefully) this weekend. If I get it done, I'll chime in and let you know what the results were.

[hartbraker]

The motor is supposed to idle high. It's cold, it needs choked just like any other gas motor to help it get up to operating temperature more quickly. If you adjust the "high" choke idle down, when the choke disengages (by tapping the gas as others have mentioned) you run the risk of the idle not being high enough for the motor to stay running. You might wanna consider that before doing any adjustments as the quadrajets are very finiky about their tuning.
In general, with these old trucks... aside from doing a motor overhaul, unless you are very knowledgable with these motors (which you've stated you are not) I would recommend not fixing what isn't broke. If they're stilling running right 25 years after assembly... I'd say somebody did something right and you shouldn't mess with it.
Lastly I second what the above posts say about the selector valve or switch. If you push the switch and can hear the valve trying to move then your selector valve may need messed with. If it doesn't make a noise when pressing the switch, check for power. If there's no power, check for fuses and grounds. Grounds may be the likely issue.

[86swb]

Both of mine do the same. It is made to idle high as said abouve when cold. Just drive it. But would lit it warm up some first.

[trimmy]

I understand there is a high idle on carb trucks. I know how they run and operate. My work had the same truck and this truck idles way higher then the work truck did and it ran just as good as my current truck, it just seem way to high to me.